One unopened bag of crab boil is sufficient for 4 pounds of shrimp, 4 pounds of crawfish or 1 dozen crabs. To a large cooking container add 3 quarts of water, 4 tbsp. of salt, 1 unopened bag of Zatarain's Crab Boil, and 1 lemon (quartered). Add cayenne pepper to taste, if desired. Bring water mix to rolling boil. Add seafood: bring to a boil. Boil crabs vigorously for 5 minutes, crawfish 2 minutes, and shrimp 1 minute. Allow seafood to remain in water for 15-20 minutes after boiling. Adding 2 tbsp. of vinegar to the water makes crabs easier to pick.